Google Tag Manager and CMS editor toolbar conflict with Kentico 7?

I just added a Google Tag Manager script to a client site which is running Kentico 7. I added the code to the master template directly so that I could place it immediately after the opening HTML body tag, per Google's recommendation. After doing so, the WYSIWYG toolbar in the Kentico CMS Desk no longer appears. I tried moving the GTM code to the HTML head, but it produced the same results. Removing the script immediately returned the toolbar to it's working state. Any ideas?